Alkyl phenol ethoxylates Biodegradability

SAE can be generally utilized as biodegradable detergents or surfactants for many industries in which the conventional alkyl-phenol ethoxylates have been used. 

In contrast to alkyl phenol ethoxylates the class of fatty alcohol ethoxylates is biodegradable and eco-friendly. Efficient technical surfactants found in this class are Lutensol XL 700, Lutensol T08, Lutensol A07, Lutensol AO8 and Eusapon OD. The phase behaviour was characterised in systems of type H20/NaCl-suet-technical non-ionic surfactant. The salt mass fraction was kept constant at = 0.10 and the oil volume fraction at = 0.50. In view of the degreasing process, which is conducted at 30°C, the X-point of the optimal system should be located around 30°C and the formation of the highly viscous La-phase should be suppressed. Figure 10.5 presents the T-y cuts for the respective systems. 

Alkyl Phenol Ethoxylates These are prepared by reaction of ethylene oxide with the appropriate alkyl phenol. The most common surfactants of this type are those based on nonyl phenol. These surfactants are cheap to produce, but they suffer from the problem of biodegradability and potential toxicity (the by product of degradation is nonyl phenol which has considerable toxicity). Despite these problems, nonyl phenol ethoxylates are still used in many industrial properties, due to their advantageous properties, such as their solubility both in aqueous and nonaqueous media, their good emulsification and dispersion properties, etc. 

Steinle et al. [426] studied the primary biodegradation of different surfactants containing ethylene oxide, such as sulfates of linear primary alcohols, primary oxoalcohols, secondary alcohols, and primary and secondary alkyl-phenols, as well as sulfates of all these alcohols and alkylphenols with different degrees of ethoxylation. Their results confirm that primary linear alcohol sulfates are slightly more readily biodegradable than primary oxoalcohol sulfates and that secondary alcohol sulfates are also somewhat worse than the corresponding linear primary. 

It is estimated that more than half of all fatty alcohols produced are ethoxylated prior to any further use. The dominance of f. as nonionic surfactants is increasing due to the fact that petrochemical alkyl phenol ethers are less biodegradable and have higher toxicity to fish. 

Alkylphenol Ethoxylates (APE). The hydrophobes of most commercial APE are made by reacting phenol with either propylene trimer or diisobutylene to form nonylphenol or octylphenol. These products contain an aromatic moiety and extensive branching in their alkyl chains. It has been shown that APE biodegrade more slowly and less extensively than LPAE (3.15-20). The difference is more pronounced when the treatment system is operating under stress conditions such as low temperatures and high surfactant loadings. 

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